Process for producing printing-plates.



UNITED sanrn PA cram GEORGE E. CORNWALL, OF RYE, NEW YORK, ASSIGNOB, BYMESNE ASSIGNMENTS, TO

JAMES G. COFFIN, TRUSTEE.

PROCESS FOR PRODUCING PRINTING-PLATES.

No Drawing.

Specification of Letters Patent.

Application filed March 20, 1905, Serial No. 251,095. Renewed July 6,1916. Serial No.

To all whom it may concern:

Be it known that I, GEORGE E. CORNWALL,

a citizen of the United States, residing at Rye, in the county ofWestchestenand State of New York, have invented a new and useful Processfor Producing Printing-Plates, of which the following is aspecification.

The invention relates to the production of planographic printing plates.An object of the invention is to produce a printing plate of greatdurability, which is capable of yielding work of a high quality and atgreat speed, which is easily and inexpensively made, and to provide amethod for producing such a plate. These and other objects of theinvention will more fully appear from the following description.

The invention consists in the novel steps, processes, and improvementsherein shown and described.

It has heretofore been well-known that particular substances possessingcertain natural properties, or being of a particular chemicalcomposition, are adapted to form the elements of a planographic printingsurface. Planographic printing surfaces have generally consisted of twosubstances possessing natural properties, respectively, whereb onesubstance will act as the ink-taking eliement and the other substance asthe inkrejectin element. In the case of certain materia s, chemicalchanges are induced in these elements whereby the tendency to take orreject ink due to natural properties is enhanced, or this property orquality is created. It is also known in the art that single substances,of a colloidal or gelatinous nature, are adapted to act as both theink-rejecting and ink-taking elements of a planographic printing surfaceby reason of changes wrought in their chemical composibut withoutchangin the chemical constitutron or identity of t e material, and beingindependent of the normal properties or chemical constitution of thesubstance or material. There are various materials or substances whichmay be made, by means of changes effected in their physical state orcondition, by means of the process included in this invention, to act asboth the ink-taking and ink-rejecting elements of a planographicsurface. Among such materials are some of the metals, and glass.

The process included in the invention has in view that the portions ofthe material which are to form the ink-rejecting parts of the surfaceshall be put in such physical state or condition that they may becapable of acting as such ink-rejecting part, and that the portions ofthe material which are to form the ink-taking parts shall be put in suchphysical state or condition that they may be capable of acting as suchink-taking part, and that the said ink-rejecting and ink-taking parts bedisposed with respect to each other so as to form or define the designor printing effect which it is desired to produce.

Various materials are capable of being treated by the process includedin this invention so as to produce printing plates of the characterhereinbefore set forth. Among such materials are certain metals, andglass. The physical state or condition of such materials may be changedin a variety of ways, all of said ways being included within the scopeof this invention.

A suitable material, such as one of those above indicated, may bepreparedto act as such a planographic printing surface by causing oneportion thereof to assume an open, noncompacted or porous structure sothat it may be adapted to reject ink by means of capability to holdmoisture, or to hold a moisture-attracting, or other ink-rejecting,medium or material. I Other portions of the said material may be treatedin such manner as to render its surface dense, polished, compacted,indurated, or otherwiseadaptingit to act efficiently as the ink-takingpart of the planographic printing surface. Placin this part of thematerial in one of the physical states or conditions mentioned willeffect this result, for the reason that materials in such physical stateor condition are adapted to resist the action of moisture-applying meansand will therefore take ink readily, as printing inks will adhere to drysurfaces.

- As illustrating one manner of. putting the process into practice, asuitable material may be taken, such as the metal zinc. The surface ofthe metal may be rendered dense or indurate by rolling or polishing, orin other suitable manner, and the design may then.v be, laid on in anysuitable resistant material, such as' a sensitive asphalt, which is thenexposed to light so as to harden it. The surface of the plate outsidethe design may then be treated so as to bring it into physical state orcondition suitable for the ink-rejecting part of the printing surface.This may be done, as before indicated, by renderingthe surfacenon-compacted or of otherwise open structure, as by graining eithermechanically or otherwise, the resist meanwhile serving to protect thedesign, and to preserve it in its desired physical state'or condition. Amaterial dissolved in an aqueous solvefit, such as a gum, may now beapplied in solution to the surface and dried. A non-aqueous solvent,such as benzol, or chloroform, may be used to dissolve the resist fromthe [design part. A plate will thus be produced having a planographicprinting surface consisting of a single material, but having a part ofits surface in such physical state or condition as to reject ink andhaving another part of its surface in such physical state or conditionas to take ink.

As illustrating another manner of putting into practice the processincluded in this invention, the entire surface of the plate may beplaced in condition to reject ink, as by A, placing it in a dense orcompacted state or condition, which may be done by giving the surface ahigh polish. The design may be laid thereon in sensitive asphalt, orother proper resistant material, in a manner known to the art, and theremainder of the surface may then be slightly roughed or etched with anetching agent, such as an acid solution. That'part of the surface isthen in condition to readily take and hold an electrolytic deposit. Theplate is placed in 50.

an electrolytic bath and receives a deposit of the same metal on itssurface except where protected by the resist covering the part which isto constitute the design. The resist may then be removed.

The surface of the plate produced by the process as thus carried outwill consist of a single material in two physical states or conditions,one art being ink-rejecting and the other ink-ta ing. In this case thisresult is realized by the design portion of-the plate having beenrendered of a comparatively dense or compacted structure and thenondesign part of a comparatively open or noncompacted structure.

The invention, in its broader aspects, is

not limited to the particular manner or means for carrying outthe-process hereln described, nor to any particular manner or means, aschanges may be made without departing from the main principles of theinvention and without sacrificing its chief advantages.

What I do claim as my invention and desire 'to secure by Letters Patent,is: 1. The process of producing a metal pla- -nographic printing platehaving a printing tory to placing ink or like design defining materialthereon, as will put it in such physical state or condition as to vmakeit ink taking to form the design element of the printing surface.

2. The process of producing an all metal planographic printing platewhich comprises compacting the metal of that portion of the surface ofthe plate which is to constitute the design and, rior and preparatory toplacing ink or like design defining material thereon, renderingnon-compact the non-design or ink-rejecting portions of said surface.

3. The process of producing a planegraphic printing plate having aprinting surface consisting of a single metal which comprises induratinga part of the surface of said metal to adapt it as the ink-takingelement of the plate and treating the remainder of said surface so thatit may have an open or non-compacted structure to adapt it to act as theink-rejecting element of the late.

4. T e process of producing a lanographic printing plate having aprinting surface consisting of a single material which consistsinpolishing a part of the surface of said material which is to constitutethe ink-taking'element of the plate and graining the remainder of thesurface so that it may form the non-printing part of the plate.

5. The process of producing a plumgraphic printing plate having aprinting surface consisting of a single metal which consists inpolishing a part-of the surface of said metal which is to constitute theinktaking element of the plate and graining or ink taking element of theprinting surface and rendering minutely cavitated the surface portionthereof which is to constitute the non-design portion.

7. The process of producing a metal planographic printing plate whichcomprises rendering dense and smooth the metal of the plate in thatportion of the surface which is to constitutethe design or inktakingelementof the printing surface and rendering minutely cavitated themetal of the plate in that portion of the surface which is to constitutethe non-design or inkrejecting portion of the surface of the plate.

8. The process of producing a planographic printing plate which consistsin providing a plate one of whose surfaces is ink-taking, smooth andconsists of a single metal, arranging a design of ink-taking material ona portion of the said surface and in the plane of the other portions ofthe said surface, covering the said design with a substance capable ofresisting the action of a graining agency, graining the non-design orsaid other portions of the said surface to render themv ink-rejectingand water-holding and then removing the substance which covers thedesign.

In testimony whereof I have signed my name to this specification in thepresence of two subscribing witnesses.

' GEORGE R. CORNWALL.

